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Intensified industrial activities significantly threaten farmland soil integrity, particularly in salinized regions. However, comprehensive evaluations of soil fertility and contamination by polycyclic aromatic hydrocarbons (PAHs) remain limited. In this study, we assessed soil quality in China’s Yellow River Delta (YRD) by quantifying 13 indicators of soil physicochemical and biological properties, along with 11 PAHs. Our findings reveal that the minimum data set approach provides a robust and comprehensive representation of overall soil fertility. Salinity emerged as the primary limiting factor, with strong correlations between salinity and key ions, highlighting its adverse effects on soil structure and function. Additionally, significant PAH contamination was detected, particularly from benzo[a]anthracene (BaA), fluoranthene (Flu), and chrysene (Chr), as indicated by the Nemerov pollution index. A pronounced negative correlation between the soil quality index (SQI) and the soil environmental index (SEI) underscores the substantial role of PAH pollution in soil degradation. Notably, the SQI integrates both SEI and soil fertility, providing a holistic assessment of soil health. These findings highlight the utility of SQI as a diagnostic tool for evaluating soil degradation and emphasize the need for targeted remediation strategies to address salinity and PAH contamination, thereby promoting soil restoration and agricultural sustainability. [ABSTRACT FROM AUTHOR]

Abstract Intensified industrial activities significantly threaten farmland soil integrity, particularly in salinized regions. However, comprehensive evaluations of soil fertility and contamination by polycyclic aromatic hydrocarbons (PAHs) remain limited. In this study, we assessed soil quality in China’s Yellow River Delta (YRD) by quantifying 13 indicators of soil physicochemical and biological properties, along with 11 PAHs. Our findings reveal that the minimum data set approach provides a robust and comprehensive representation of overall soil fertility. Salinity emerged as the primary limiting factor, with strong correlations between salinity and key ions, highlighting its adverse effects on soil structure and function. Additionally, significant PAH contamination was detected, particularly from benzo[a]anthracene (BaA), fluoranthene (Flu), and chrysene (Chr), as indicated by the Nemerov pollution index. A pronounced negative correlation between the soil quality index (SQI) and the soil environmental index (SEI) underscores the substantial role of PAH pollution in soil degradation. Notably, the SQI integrates both SEI and soil fertility, providing a holistic assessment of soil health. These findings highlight the utility of SQI as a diagnostic tool for evaluating soil degradation and emphasize the need for targeted remediation strategies to address salinity and PAH contamination, thereby promoting soil restoration and agricultural sustainability.

In this study, geostatistical techniques were used to investigate spatial variability of physico-chemical properties of soil samples from farming- and artisanal gold mining-affected areas. Based on coefficients of variation, chemical properties, except pH, had high variability compared to physical properties. This could be attributed to the local lithology, vegetation cover and land-use. Spatial distribution patterns of silt, clay, total nitrogen, pH and C/N could be controlled by extrinsic factors such as biological activity and land-use patterns, whereas those of electrical conductivity, organic matter (SOM) and sand were governed by both intrinsic and extrinsic factors. Because of the dominance of clay type, the distribution of cation exchange capacity (CEC) was spatially correlated with clay. About 80% of the area had acidic to circumneutral pH, which may increase mobility and toxicity of most cationic heavy metals. Distribution maps showed that microbial activities, expressed as C/N ratios, tend to be weak around farmlands, reflecting the impacts of soil management practices. In contrast, abundance of clay around the river bank is an indication of soil erosion and its redistribution from upland to depositional areas. Mean error and root mean square error of kriging were higher than those of cokriging for SOM, suggesting that cokriging was more reliable for spatial interpolation of this variable. The work reported in this study indicated that that 29%, 77% and 75% of the area had high probabilities to have pH, CEC and SOM contents below which most cationic heavy metals would be mobile and bioavailable in the soils.

The study aimed to evaluate the soil environmental characteristics of Vinh Long Province's perennial crop-growing area using principal component analysis (PCA) and cluster analysis (CA). Soil environmental quality data were collected in eight districts of Vinh Long province for 27 physical and chemical parameters. CA and PCA analysis was used to group and identify critical parameters affecting perennial crops' soil environment. The findings demonstrate low to moderate soil compaction porosity, buffering capacity, and structure for perennial crops. In addition, the soil has a low pH, electrical conductivity, total soluble salts, aluminum, and cation exchange capacity. Although rich in nutrients, the content of organic matter, available phosphorus, cations, and trace elements is only low to moderate. CA results showed three districts suitable for strongly developing perennial crops: Tra On, Mang Thit, and Vung Liem. The PCA results showed that except for density, the buffer capacity of the soil, and dissolved Al3+, the upcoming monitoring program must incorporate all remaining criteria. The study's findings offer crucial information to help the management organization devise strategies for enhancing and sustainably expanding perennial crops in the province. It is necessary to further evaluate the soil's environmental quality over time and soil depth and determine the frequency of monitoring in the study area. [ABSTRACT FROM AUTHOR]

BackgroundHeavy metal pollution in cultivated land will affect crop yield and quality, as well as groundwater quality, ecological security, and human health.ObjectiveTo analyze the pollution status of heavy metal elements such as chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) in cultivated soils of the Donghe River Basin in Chenzhou City, and to evaluate the environmental quality of local cultivated soil.MethodsA total of 16 samples of cultivated soil from the Donghe River Basin in Chenzhou City were collected, and the contents of Cr, Cu, Zn, As, Cd, and Pb in the samples were determined by inductively coupled plasma mass spectrometry. The Nemerow comprehensive pollution index method (the evaluation indicators included both Nemerow comprehensive pollution index and single pollution index), the geological accumulation index method, and the potential ecological risk index method were used to evaluate the soil environmental quality.ResultsThe average levels of Cr, Cu, Zn, As, Cd, and Pb in the soil samples in the study area were 58.25, 49.50, 273.88, 137.76, 2.92, and 672.29 mg·kg−1, respectively. The average values of Cu, Zn, As, Cd, and Pb were all exceeded the background values of soil elements in Hunan Province. The single pollution indices of As, Cd, Pb, and Zn in soil were 4.40, 9.74, 5.85, and 1.15 respectively. The contamination of As and Pb reached 93.75% and 81.25% respectively. The geological accumulation indices of soil As, Cd, Pb, and Zn were 2.11, 3.71, 2.97, and 0.58, respectively, which showed heavy Cd pollution, moderate As and Pb pollution, and slight Zn pollution. The potential ecological hazard indices of soil Cr, Cu, Zn, As, Pb, and Cd were 1.63, 9.07, 2.90, 87.75, 113.18, and 695.76. 81.Twenty five percent of Cd samples showed heavy pollution and above, and 62.50% of Pb samples had moderate pollution and above. The Nemerow comprehensive pollution index was 7.72, which belonged to heavy pollution; and the comprehensive potential ecological risk index was 910.29, which belonged to high ecological risk.ConclusionThere are certain differences in the results of different evaluation methods. The cultivated soils of the Donghe River Basin in Chenzhou City, is seriously polluted by heavy metals, and Cd, As, and Pb are the main polluting elements.

Trace elements in farmland soil are important indicators of soil quality and farmland health, and also maintain the nutrient balance and promote the healthy growth of plants. In this study, taking Conghua District of Guangzhou city as the study area, the effects of topography, soil, land use, and other factors on trace elements in soil were investigated, and the spatial variability of boron (B), manganese (Mn), molybdenum (Mo), copper (Cu), and zinc (Zn) in farmland soil in a typical red soil region were mapped using a geographically weighted regression (GWR) method. The pH and land economic index (LEI) were important factors affecting the changes in trace element concentrations in the five soils, and the Cu and Zn concentrations were clearly affected by human factors. In the study area, 86.99% of B measurements were classified as low and very low levels, 50.61% and 49.20% of Mo measurements were also low and very low, 71.79% of Mn measurements were classified as moderate, while 91.02% of Cu and 52.95% of Zn measurements were classified as high. After a cross validation, the GWR Kriging (GWRK) model results of each element were relatively stable, and the order of the fitting coefficient (R2) was Cu > Zn > B> Mn > Mo. This study clarifies the spatial distribution and influencing factors of soil microelements in the studied region. This information can be used to improve the nutrient imbalance, further guide agricultural production, strengthen the management of farmland, and improve the healthy productivity of cultivated land.

A model integrating geo-information and self-organizing map (SOM) for exploring the database of soil environmental surveys was established. The dataset of 5 heavy metals (As, Cd, Cr, Hg, and Pb) was built by the regular grid sampling in Hechi, Guangxi Zhuang Autonomous Region in southern China. Auxiliary datasets were collected throughout the study area to help interpret the potential causes of pollution. The main findings are as follows: (1) Soil samples of 5 elements exhibited strong variation and high skewness. High pollution risk existed in the case study area, especially Hg and Cd. (2) As and Pb had a similar topo-logical distribution pattern, meaning they behaved similarly in the soil environment. Cr had behaviours in soil different from those of the other 4 elements. (3) From the U-matrix of SOM networks, 3 levels of SEQ were identified, and 11 high risk areas of soil heavy metal-contaminated were found throughout the study area, which were basically near rivers, factories, and ore zones. (4) The variations of contamination index (CI) followed the trend of construction land (1.353) > forestland (1.267) > cropland (1.175) > grassland (1.056), which suggest that decision makers should focus more on the problem of soil pollution surrounding industrial and mining enterprises and farmland. [ABSTRACT FROM AUTHOR]

This study assessed soil pollution in the Varanasi environs of Uttar Pradesh in India. Assessing the concentration of potentially harmful heavy metals in the soils is imperative in order to evaluate the potential risks to human. To identify the concentration and sources of heavy metals and assess the soil environmental quality, 23 samples were collected from different locations covering dumping, road and agricultural area. The average concentrations of the heavy metals were all below the permissible limits according to soil quality guidelines except Cu (copper) and Pb (lead) in dumping and road soils. Soil heavy metal contamination was assessed on the basis of geoaccumulation index (Igeo), pollution index (PI) and integrated pollution index (IPI). The IPI of the metals ranged from 0.59 to 9.94, with the highest IPI observed in the dumping and road soils. A very significant correlation was found between Pb and Cu. The result of principal component analysis suggested that PC1 was mainly affected by the use of agrochemicals, PC2 was affected by vehicular emission and PC3 was affected by dumping waste. Meanwhile, PC4 was mainly controlled by parent material along with anthropogenic activities. Appropriate measures should be taken to minimize the heavy metal levels in soils and thus protect human health. [ABSTRACT FROM AUTHOR]

Abstract: Over the past few decades, numerous concerns have been raised in China over the issue of environmental sustainability. Various soil survey and monitoring programs have been carried out in China to study soil quality, and to provide a scientific basis for environment policy making. This paper provides an overview of past and current soil quality surveys and monitoring activities in China. This paper includes a summary of concerns over background concentrations of elements in soil, and soil environmental standards and guidelines in China. Levels of pollution in urban soil, agricultural soil, and soil in mining and smelting areas were compared using the concentrations and pollution indexes. In addition to soil surveys, soil monitoring is essential to study the data and to examine the effects of contaminants in soils. However, the current soil quality monitoring system was insufficient to accurately determine the soil quality status of soils across China. For accurate soil monitoring in China, it will be necessary to set up routine monitoring systems at various scales (national, provincial, and local scales), taking into consideration monitoring indicators and quality assurance. This is currently an important priority for the environmental protection administration of China. [Copyright &y& Elsevier]

We take three types of tidal marshes in Shanghai City as the study object: tidal marshes in mainland, tidal marshes in the rim of islands, and shoal in Yangtze estuary. On the basis of assessing nutrient quality and environmental quality, respectively, we use soil quality index( SQI) to assess the soil quality of tidal flats, meanwhile formulate the quality grading standards, and analyze the current situation and characteristics of it. The results show that except the north of Hangzhou Bay, Nanhui and Jiuduansha with low soil nutrient quality, there are not obvious differences in soil nutrient quality between other regions; the heavy metal pollution of tidal marshes in mainland is more serious than that of tidal marshes in the rim of islands; in terms of the comprehensive soil quality index, the regions are sequenced as follows: Jiuduansha wetland > Chongming Dongtan wetland > Nanhui tidal flat > tidal flat on the periphery of Chongming Island > tidal flat on the periphery of Hengsha Island > Pudong tidal flat > Baoshan tidal flat > tidal flat on the periphery of Changxing Island > tidal flat in the north of Hangzhou Bay. Among them, Jiuduansha wetland and Chongming Dongtan wetland have the best soil quality, belonging to class III, followed by Nanhui tidal flat, tidal flat on the periphery of Chongming Island and tidal flat on the periphery of Hengsha Island, belonging to class IV; tidal flat on the periphery of Changxing Island, Pudong tidal flat, Baoshan tidal flat and tidal flat in the north of Hangzhou Bay belong to class V. [ABSTRACT FROM AUTHOR]

Identifying the driving factors of soil environmental quality is critical in raising countermeasures for managing the soil environment efficiently and precisely. In 2018, China issued risk control standards to divide soil environmental quality into three classes to meet the demands of environment management. However, there is a lack of knowledge of this new standard. An intensive field-sampling research (2598 top-soil samples were analyzed) was conducted in the agricultural land of Hubei province, central China, to find the driving factors of pollutants based on this new standard. According to the standard, the proportion of classes 1, 2, and 3 in the overall quality grade was 57.3%, 41.7%, and 1%, respectively. The standardized index showed that the pollution levels of cadmium, arsenic, lead, and chromium were higher than that of mercury. The first component of the principal component analysis explained 56.4% of the total variance, and the loading of cadmium, arsenic and lead were -53.5%, -52.1%, and -51.2%, respectively. The general linear modeling found that cadmium and arsenic showed positive and significant effects ( p < 0.001) on the grading results of soil environmental quality. Based on the random forest algorithm, cadmium showed the greatest importance on soil environmental quality (increase in mean squared error = 32.5%). Overall, this study revealed that cadmium, arsenic, and lead were driving pollutants affecting soil environment quality grade. The large data size increased the reliability and robustness of the study's conclusions, and it provided reference methods for future studies investigating China's new standard for assessing soil environmental quality.

Trace elements in farmland soil are important indicators of soil quality and farmland health, and also maintain the nutrient balance and promote the healthy growth of plants. In this study, taking Conghua District of Guangzhou city as the study area, the effects of topography, soil, land use, and other factors on trace elements in soil were investigated, and the spatial variability of boron (B), manganese (Mn), molybdenum (Mo), copper (Cu), and zinc (Zn) in farmland soil in a typical red soil region were mapped using a geographically weighted regression (GWR) method. The pH and land economic index (LEI) were important factors affecting the changes in trace element concentrations in the five soils, and the Cu and Zn concentrations were clearly affected by human factors. In the study area, 86.99% of B measurements were classified as low and very low levels, 50.61% and 49.20% of Mo measurements were also low and very low, 71.79% of Mn measurements were classified as moderate, while 91.02% of Cu and 52.95% of Zn measurements were classified as high. After a cross validation, the GWR Kriging (GWRK) model results of each element were relatively stable, and the order of the fitting coefficient (R2) was Cu > Zn > B> Mn > Mo. This study clarifies the spatial distribution and influencing factors of soil microelements in the studied region. This information can be used to improve the nutrient imbalance, further guide agricultural production, strengthen the management of farmland, and improve the healthy productivity of cultivated land. [ABSTRACT FROM AUTHOR]

Abstract: Assessment of pollution risk and spatial distribution for pollutant are important in the research of regional soil environmental quality. The paper provides a case of geostatistical method for predicting the probability of exceeding a Pb threshold and tracing the hotspots in sewage-irrigated land. The hotspots of Pb pollution which indicated higher risk than other areas were identified to be mainly distributed in the regions of soils irrigated with sewage. Sewage irrigation and parent material are the main sources for Pb concentration in soils of the study area, which obviously affect the distribution of Pb. The direction of high spatial continuity is consistent with the main direction of the river (Yongding River). Moreover, the Pb concentrations showed more extended transportation along the main direction of Yongding River. The results of disjunctive kriging showed that, if we are only willing to accept land for vegetable production if the probability that soil lead concentrations exceed the contamination threshold is 50% or more, then 6.2% of the study area (1932 km2) would be classified as unsafe for this purpose. That avoids the difficulty in selecting the proper criterion for the probability threshold. [Copyright &y& Elsevier]

Abstract: Heavy metal concentrations in agricultural soils of Zhejiang Province were monitored to indicate the status of heavy metal contamination and assess environmental quality of agricultural soils. A total of 908 soil samples were collected from 38 counties in Zhejiang Province and eight heavy metal (Cd, Cr, Pb, Hg, Cu, Zn, Ni and As) concentrations had been evaluated in agricultural soil. It was found 775 samples were unpolluted and 133 samples were slightly polluted and more respectively, that is approximately 14.65% agricultural soil samples had the heavy metal concentration above the threshold level in this province by means of Nemerow''s synthetical pollution index method according to the second grade of Standards for Soil Environmental Quality of China (GB15618-1995). Contamination of Cd was the highest, followed by Ni, As and Zn were lower correspondingly. Moreover, Inverse Distance Weighted (IDW) interpolation method was used to make an assessment map of soil environmental quality based on the Nemerow''s pollution index and the soil environmental quality was categorized into five grades. Moreover, ten indices were calculated as input parameters for principal component analysis (PCA) and the principal components (PCs) were created to compare environmental quality of different soils and regions. The results revealed that environmental quality of tea soils was better than that of paddy soils, vegetable soils and fruit soils. This study indicated that GIS combined with multivariate statistical approaches proved to be effective and powerful tool in the mapping of soil contamination distribution and the assessment of soil environmental quality on provincial scale, which is beneficial to environmental protection and management decision-making by local government. [Copyright &y& Elsevier]

Considering the biomagnification in food chains, cadmium (Cd) contamination in paddy fields has become concerning. The remediation of soil cadmium by the addition of amendments is a common agricultural practice. However, it remains ambiguous whether amendment use decreases soil environmental quality (SEQ) and sustainability. In this study, five compound amendments with different pH were utilized in long-term Cd-contaminated paddy soils. The SEQ of all treatments was quantitatively assessed according to a comprehensive evaluation mathematical model (Criteria Importance Through Inter-criteria Correlation (CRITIC)–Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)), and the indicators involved in microbial functional gene (MFG) abundance, soil physicochemical and microbiological properties (CMP) and soil microbial function (N-related enzyme and transformation rate, N-ET) were measured. The results show that the SQE and remediation effect (expressed by the decrease in available Cd (A Cd), %) in our treatments were alkaline > natural > acidic except for D alkaline treatment. The significant contradiction between soil SQE and remediation effect in D treatment attribute to its dose effects, which inhibiting microbial nitrogen assimilation and dissimilation and therefore counteracts the promoting effect of the decrease in A Cd. Based on this discussion, three alkaline amendments (A, B and D) with similar effective remediation effect were employed in four other Cd-contaminated soils. Results indicated that both negative effect (D treatment) and promoting effect (A and B treatment) existed in the next 3 years. [Display omitted] • The new evaluation method effectively reduced the redundancy among indicators. • Underestimating the contribution of microbial functional genes to SEQ assessment. • A significant discrepancy was found between remediation effect and SEQ. • The impact of amendments on SEQ exists for a long time. [ABSTRACT FROM AUTHOR]

• We compared soil comprehensive quality between vegetable and fruit greenhouses. • We adopted minimum dataset and modified Nemerow index for soil quality assessments. • Fertility quality more impacts the greenhouse soil than environmental factors do. • High EC and low SOM were main factors to reduce the fertility of greenhouse soil. • The accumulation of Cd and Hg in topsoil threats soil environment quality. The increasing demand of fruits and vegetables has resulted in the rapid growth of plastic greenhouse production (PGP) systems worldwide. A comprehensive assessment method considering both soil fertility and environmental safety is necessary for the sustainable development of PGP systems. A total of 92 vegetable greenhouses in Jingyang County and 28 fruit greenhouses in Dali County in Shaanxi Province, China, were selected for comparing the changes of soil quality under two cultivation patterns. The soil comprehensive quality index (SQI) in Jingyang (0.53) was significantly higher than that in Dali (0.46) (p < 0.05). A significant correlation was found between the SQI and the soil fertility index (SFI) (p < 0.01), suggesting that the SQI was mainly dependent on the soil fertility level in greenhouses. The primary limiting factors of the SFI in PGP in Jingyang and Dali were low soil organic matter content (19.57 g kg−1) and high electrical conductivity (1303 μS cm−1), respectively, indicating that soil in greenhouses in Jingyang and Dali might experience nutrient deficiencies and soil salinity accumulation problems, respectively. Cd and Hg were main limiting factors of soil environmental index (SEI), especially Hg. The SEI in Dali (0.74) was significantly lower than that in Jingyang (0.81) due to differences in the geo-accumulation indexes of heavy metals in the topsoil in greenhouses. Considering that no significant difference was found in the SFI between two study areas, the SEI is likely responsible for the regional differences in the SQI in PGP. The negative correlation of the SEI with the cultivation ages of plasticulture indicated that heavy metal accumulation problems would be the primary limiting factor of the SQI in the future if greenhouses cannot be managed appropriately. Our study provides data support for soil quality management in PGP systems. [ABSTRACT FROM AUTHOR]

Soil pollution has become one of the most important environmental issues in China. It is very important to evaluate soil environmental quality comprehensively and objectively. This paper proposes a soil environment quality assessment model based on the Driving Force-Pressure-State-Impact-Response (DPSIR) model and data fusion. At first, 18 evaluation indicators are selected, including complex indexes, such as the industrialization index, heavy metal pollution index, organic pollution index, potential ecological risk index, and human health risk index, and single indexes such as population density, fertilizer/pesticide application intensity, annual average air quality index, etc. Then, hierarchical analysis model is constructed, and the weight of each indicator is calculated based on Analytic Hierarchy Process (AHP) method. According to the quartile of indicator values of 32 provincial administrative divisions on the Chinese mainland, the values of each indicator are standardized and graded. Finally, the soil environmental quality index (SEQI) is calculated by the weighted average of the standard values of the 18 indicators. The assessment model is then applied in evaluating soil quality of Hebei Province, China. The results show that the soil environmental quality of Hebei's agricultural land is in a medium state, and the industrial land is approaching the alert state. The pressure of soil pollution mainly comes from the discharge of industrial pollutants and the application of pesticides and fertilizers. Soil pollutants, such as lead, copper, zinc, benzo[a]pyrene, and benzo[a] should be especially controlled. [ABSTRACT FROM AUTHOR]